Determination of the energetic cost of swimming from the analysis of growth rate and body composition in juvenile chinook salmon, Oncorhynchus tshawytscha.

The standard metabolic rate was estimated to be 19.5 cal X kcal-1 X day-1. The multiple regression of growth on swimming speed and ration size was significant (P less than 0.001). The relationship was as follows: G = 22.22-2.85BL + 6.58 R where G is growth in cal X kcal X day-1, BL represents swimming speed in body lengths X sec-1 and R denotes ration in % body wt X day-1, dry weight. The multiple correlation coefficient, R2, was 0.80. Unlike coho salmon, the net cost of swimming was independent of swimming speed. Fish in all groups experienced reduction of fat with exercise with the exception of the slowest speed-highest ration (1.0-1.9 BL X sec-1, 6% X day-1) group. Nearly all of the explained variation was accounted for by food consumption rate.